Zombies are fun.  Decayed skin and flesh is a great opportunity to try all kinds of interesting texture effects.

In my opinion, you can't go past toilet paper dipped in thin glue when it comes to zombie flesh.  This gives a stringy, slightly lumpy texture that I think works well for conveying the idea of partially decomposed soft tissue.  The photos here are of my current zombie hand project, before painting.  In a future post, I'll give details of how I achieve a suitably undead skin tone using acrylic paints.

Yes, I'm aware the proportions of the thumb are a bit off.  This is to accommodate the beer neoprene beer cooler that I'll wrap the hand around.  Fingernails are just fingernail shaped pieces of card glued to the end of the fingers.  The  "flesh" was then wrapped around them and shaped to resemble the skin around a person's fingernails.  The little finger ends in bone, and thus doesn't have a fingernail.